Fix underflow of `nbCompares` by switching to an `int` and comparing
`nbCompares > 0`. This is a minimal fix, because I don't want to change
the logic. These loops seem to be doing `nbCompares + 1` comparisons.
The bug was reported by Dan Carpenter and found by Smatch static
checker.
https://lore.kernel.org/all/20211008063704.GA5370@kili/
Fixes the update from PR #2508. I had accidentally forgotten to rebuild
the library, and the regression test suite isn't hooked up to the new
fancy build system yet.
I've double checked that the results are deterministic.
9f327c02fd changed the compression method
for LDM, so the results are slightly different.
I've re-tested LDM on some larger inputs and everything seems fine.
These ratio changes just seem to be noise. There is generally a 0.01%
swing in ratio, sometimes better sometimes worse, but never large.
Fixes#2442.
1. When creating a dictionary keep the same behavior as before.
Assume the source size is 513 bytes when adjusting parameters.
2. When calling ZSTD_getCParams() or ZSTD_adjustCParams() keep
the same behavior as before.
3. When attaching a dictionary keep the same behavior of ignoring
the dictionary size. When streaming this will select the
largest parameters and not adjust them down. But, the CDict
will use the correctly sized parameters, which seems like the
right tradeoff.
4. When not attaching a dictionary (either forced not to, or
using a prefix dictionary) we select parameters based on the
dictionary size + source size, and assume the source size is
small, which is the same behavior as before. But, now we don't
adjust the window log (and hash and chain log) down when the
source size is unknown.
When the source size is unknown all cdicts should attach, except
when the user disables attaching, or `forceWindow` is used. This
means that when streaming with a CDict we end up in the good case
where we get small CDict parameters, and large source parameters.
TODO: Add a streaming + dictionary regression test case.
* Add a test that runs without a pledgedSrcSize and with a dictionary.
* Add github.tar data with uses the github dictionary while compressing
github.tar, instead of each file individually.
https://github.com/facebook/zstd/pull/2339 removes the single-pass zstdmt API.
This changes the compressed size, because we no longer take the # of threads into
account when deciding the job size.
* A copy-paste error made it so we weren't running the advanced/cdict
streaming tests with the old API.
* Clean up the old streaming tests to skip incompatible configs.
* Update `results.csv`.
The tests now catch the bug in #1787.
